1. Field
The present disclosure relates generally to facilitating communication over a data network. More specifically, the present disclosure relates to a method for adapting a longest-prefix-match lookup engine to accommodate hierarchically structured variable-length identifiers for forwarding data.
2. Related Art
The proliferation of the Internet and e-commerce continues to fuel revolutionary changes in the network industry. Today, a significant number of information exchanges, from online movie viewing to daily news delivery, retail sales, and instant messaging, are conducted online. An increasing number of Internet applications are also becoming mobile. However, the current Internet operates on a largely location-based addressing scheme. That is, a consumer of content can only receive the content by explicitly requesting the content from an address (e.g., IP address) closely associated with a physical object or location. This restrictive addressing scheme is becoming progressively inadequate for meeting the ever-changing network demands.
The current architecture of the Internet revolves around a conversation model, which was created in the 1970s for the ARPAnet to allow geographically distributed users to use a few big, immobile computers. This architecture was designed under the influence of the telephone network, where a telephone number is essentially a program that configures the switches along a path from the source to the destination. Not surprisingly, the designers of the ARPAnet never expected it to evolve into today'subiquitous, relentlessly growing Internet. People now expect a lot more from the Internet than the ARPAnet was designed for. Ideally, an Internet user should have access to any content, anywhere, at any time. Such access is difficult to guarantee with the current location/device-binding IP protocol.
Under current web-based naming structures, an idea of the host is implicit in the name which contains the corresponding content. For example, http://www.amazon.com/index.html can be found by contacting the machine www.amazon.com. However, this contact requires a Domain Name System (DNS) to translate a human-readable host name into an IP address (e.g., 209.34.123.178). In current computer systems, there is no way to refer to a piece of content without knowing what host that file is stored on, and even then the contents associated with that file might change.
In the current technology, forwarding is the process by which a node in a packet-switched network transmits a packet from a source address to a fixed-length destination address. An Internet Protocol (IP) forwarder is typically called a router. The router receives a packet at one of its input ports (i.e., network interface). Next, the router uses a longest-prefix-match lookup engine to find an output port to which the packet should be forwarded based on the packet's destination address. Subsequently, the router sends the packet to the output port, which is usually different from the input port. The lookup engine in an IP forwarder uses a longest-prefix-match because more than one lookup engine entry can match the destination address. Although the current IP router technology works well with IP packets, which have fixed-length IP addresses, such routers cannot handle packets with variable-length identifiers.